Spray sides of Crockpot with cooking spray or use a Crockpot liner.
Mix together chili powder, garlic powser, onion, pinto beans, tomoato sauce and diced tomatoes in a medium sized bowl.
Place 3/4 cup tomato mixture in bottom of Crockpot. Spread refried beans onto a tortilla.
Place tortilla in Crockpot. Sprinkle with 1/3 cup shredded cheese. Spread 3/4 cup tomato mixture on top. Continue the process, alternating tortillas, cheese and tomato mixture until you end with cheese on the top.