Preheat the oven to 375 degrees F (190 degrees C).
Add Carrot (3), Cauliflower Florets (1 1/2 cup), Sweet Onion (1/2), Pecan Halves (1 cup), Garlic (2 clove), Chili Powder (1 teaspoon), Ground Cumin (1/2 teaspoon), Chipotle Seasoning (1/4 teaspoon), and Sea Salt (1/2 teaspoon) to the bowl of a food processor. Pulse all ingredients until the mixture is evenly ground yet still has some smaller chunks, approximately 10-15 seconds.
Transfer vegan taco "meat" to a greased baking sheet and spread into a single layer. Bake for 20-22 minutes, stirring halfway through to prevent over-browning. You want the carrots and cauliflower to be cooked but not mushy, leaving it with a slightly crunchy texture.
Allow the mixture to cool slightly, then divide evenly among Butter Lettuce (12 piece), approximately 1/4 cup mixture for each lettuce leaf.
Top with Avocado (1) and Fresh Cilantro (to taste), then serve! If you're not worried about keeping this vegan, sour cream or Cotija cheese would be great additions as well!