Place the chicken breasts in the crockpot and pour the salsa and diced tomatoes over them. Add the garlic powder, onion powder, cumin, and chili powder. Stir to combine.

Cover and cook on low for 6-8 hours or on high for 3-4 hours, until the chicken is cooked through and easily shreds with a fork.

Once cooked, shred the chicken in the crockpot using two forks. Add the softened cream cheese and shredded cheddar cheese to the chicken mixture. Stir until the cheese is melted and well combined.

Heat a large skillet over medium heat and lightly grease with cooking spray or oil.

Place a tortilla in the skillet, and spoon a generous amount of the chicken and cheese mixture onto one half of the tortilla. Fold the other half over to create a half-moon shape.

Cook for 2-3 minutes on each side, or until the tortilla is golden brown and crispy. Repeat with the remaining tortillas and filling.

Slice the quesadillas into wedges and serve warm with your favorite toppings, such as sour cream, guacamole, or extra salsa.