To make this ahead of time, you can make TVP taco meat and chop up the veggies first. Store them in separate containers, and only assembly them when ready to enjoy.  TVP taco meat can be stored in the fridge for 4-5 days and frozen for up to 2 months in a sealed container. To reheat, heat it in the microwave or on the stove until thoroughly heated. Let the frozen ones thaw in the fridge or countertop before reheating.