Start by preparing the shrimp. If frozen, remove from bag and place in colander. Run cool water over them until they thaw. Peel and devein.
Pre-heat oven to 350F (to warm tortillas), wrap tortillas in foil and place in oven.
Chop the onion and tomatoes.
Pour olive oil into frying pan and add shrimp, southwest seasoning, Tex Mex seasoning, lemon pepper, garlic powder, Worcestershire sauce, and BBQ sauce. Since shrimp cook really fast I like to add everything to the pan before I turn on the heat. Once you have all the ingredients in the pan, mix them up and spread the shrimp out so none are on top of each other.
Cook the shrimp on medium-high heat for about 5 minutes, until the sauce reduces a bit.
Top tacos with shrimp, sour cream, salsa, onions, and tomatoes.