Under Nebraska Law, covenant not to compete is an asset of a corporation which passes by operation of law to a successor corporation as the result of a merger, regardless of whether the agreement would otherwise be assignable. AON Consulting, Inc. v. Midlands Fin. Benefits, Inc. 748 N.W.2d 626, 639 (Neb. 2008). Thus, the fact that your first employer merged with its competitor does not alter the fact that the covenant is likely to some extent enforceable.
Nebraska courts look at the following issues to determine whether a covenant not to compete is valid: whether the restriction is "(1) reasonable in the sense that it is not injurious to the public, (2) not greater than is reasonably necessary to protect the employer in some legitimate interest, and (3) not unduly harsh and oppressive on the employee." Id. at 638. Here, application of the non-competition agreement to include the entire US would be unduly harsh and oppressive and against public policy
. In the employment context, the validity of a covenant not to compete aimed at preventing a former employee from unfairly appropriating customer goodwill is no greater than reasonably necessary only if it restricts the former employee from working for or soliciting the former employer's clients or accounts with whom the former employee actually did business and had personal contact. The Supreme Court of Nebraska applies this test strictly.
Thus, a court would likely strike down the agreement as overly broad, or reduce the area of competition as to an area which is more reasonably limited in geographic coverage. It is more likely that they will strike it down as Nebraska law does not favor rewriting an agreement to make it enforceable. H & R Block Tax Servs. v. Circle A Enters., 693 N.W.2d 548 (Neb. 2005).
If this clause is to be interpreted under Nebraska law, you have a good chance to actually "bust" the clause.
However, you've stated that Delaware law is applicable, so it is actually a question of what the law of Delaware is on non-competition agreements.
Under Delaware law, the merger does not affect the validity or applicability of the non-competition agreement. In Delaware the court look to whether the covenant is supported by an exchange of adequate consideration. All Pro Maids, Inc. v. Layton, 2004 WL(NNN) NNN-NNNNat *2 (Del Ch. 2004)(citing Research & Trading Corp v. Pfuhl, 1992 WL 345465 at *9 (Del Ch. 1992)). Contracts in restraint of competition are, however, subject to some special requirements. To wit, a covenant not to compete must be reasonable in geographic scope and temporal duration, must advance a legitimate economic interest of the party seeking its enforcement, and must survive a balancing of the equities in order to be enforceable. Tristate Courier, 2004 Del. Ch. LEXIS 43, 2004 WL 835886, at *10 & n.126.
You stated that you received a two week severance, this could be seen as independent consideration for the non-competition agreement (and has been interpreted as such by both Nebraska and Delaware courts). Significantly, under Delaware law:
"The reasonableness of a geographical limitation in a non-competition agreement should not be judged merely in terms of absolute physical distances. The purpose of such a covenant is to protect an employer's goodwill in a given market. If this market, or more accurately, the employer's customer base, extends throughout the nation, or indeed even internationally, and the employee would gain from the employment some advantage in any part of that market, then it is appropriate that an employee subject to a non-competition agreement be prohibited from soliciting those customers on behalf of a competitor regardless of their geographic location."
Del. Express Shuttle, v. Older, 2002 Del Ch. LEXIS 124 (Del Ch. 2002).
In Delaware Express Shuttle, the employee worked for the service until he was asked to resign. He signed a negotiated non-competition agreement and went to work in his previously-owned travel agency. However, he purchased a competing shuttle service and expanded that aspect of the business, which he built up with the service's former customers. The service brought an action and the court concluded that defendants did in fact violate the terms of the unambiguous non-competition agreement and that none of the equitable defenses raised had merit. An injunction against further competition with the service for a reasonable period of time and area was issued, and a small damage award was made. Although the customer list was misappropriated by defendants, the court held that the list did not constitute a trade secret under the Act because it consisted of public information. However, further use thereof was enjoined. The court awarded nominal damages based on defamatory remarks made by defendants that the service was heading into bankruptcy. All other defamation claims as well as claims regarding tortious interference with existing or prospective business relationships were rejected.
So, the question of whether the entire nation would be too large of a geographic area which bars you from competing would be a question of fact which the court must answer. It would depend on whether your ex-employer has a legitimate interest in keeping you from acting in the entire nation and whether your new job is actually in competition with them or causes them any loss.
This being the case, do you believe that you could obtain a release from your ex-employer on this non-competition agreement if you continue with the non-solicitation agreement, in order for you to be able to get employment in your field elsewhere?