In a large skillet over medium-high heat, add the chicken, mushrooms, and onion. Cook until chicken is cooked through, about 5 minutes.
Add the garlic powder, chili powder, cumin, salt, black pepper, and cayenne pepper. Stir to combine and cook for 1 minute.
Pour in the water and bring to a boil. Reduce heat and simmer for 5 minutes.
Remove from heat and let cool slightly.
Lay out the tortillas and spoon 1/4 cup of the chicken mixture into each one. Fold up the sides and roll up to close.
In a large skillet or deep-fryer, heat the oil over medium-high heat. Carefully add the chimichangas to the oil and fry for 3-4 minutes, flipping once, until golden brown and crispy.
Remove from heat and drain on paper towels.
Serve with your favorite toppings such as salsa, sour cream, and guacamole.
Interesting Facts
Chimichangas originated in Mexico in the 1950s.
Chimichangas are often filled with beans, cheese, and beef.
The name "chimichanga" may have come from the Mexican slang word "chimenea," which means "hot mess."