Preheat the oven to 350 degrees. Grease a loaf pan or small casserole dish well.
In a saucepan over medium heat, whisk together the tomato sauce, butter, garlic, cumin, chili powder, onion powder, a pinch of salt, a dash of cayenne pepper, and a pinch of keto sweetener if desired. Simmer for 5 minutes.
Add the shredded chicken to a bowl. Toss with a squeeze of lime juice and ¼ of the sauce mixture.
Fill a homemade keto tortilla with the chicken mixture.
Roll the tortilla close, then place in the prepared pan, seam-side down. Repeat with remaining tortillas and chicken mixture.
Top with the rest of the sauce.
Bake in the oven for 15 minutes.
Remove from the oven and garnish with chopped avocado, fresh cilantro, and sour cream (omit if dairy free) before serving.