Your most likely nexus would be most closely associated with your home residence state. Merely working in a coffeeshop or airport as you pass through town like a tumbleweed does not establish nexus.
Whether you claim any home office expenses as tax deductions is irrelevant to nexus.
If you are completely itinerant and live wherever you hang your hat and plug in for a re-charge, you could argue that nexus is related to wherever you are at the moment. But chances are, you get your mail delivered to some fixed address somewhere.
This would also be the town that you likely have your bank account established. Therefore, a money trail will lead you back to that state as your primary business location.
If you want true legal protection with your LLC, you will likely need to register your LLC as a foreign LLC with your home state as well. If not, you would not have the authority to sue anyone from your home state; you would need to use a Delaware court to sue someone who stiffs you.