Step 1: Prepare the Seasoned Chicken: In a medium skillet, heat the olive oil over medium heat. Add the shredded chicken, chili powder, cumin, smoked paprika, garlic powder, onion powder, and cayenne pepper (if using). Stir well to coat the chicken evenly.
Step 2: Simmer the Chicken: Pour in the chicken broth or water. Bring to a simmer and cook for 3-5 minutes, stirring occasionally, until the liquid has mostly evaporated and the chicken is thoroughly heated through and coated in the spices. Taste and adjust seasoning with salt and pepper as needed. Remove from heat.
Step 3: Prepare Toppings: While the chicken simmers, prepare all your desired toppings: shred lettuce, dice tomatoes, slice red onion, crumble cheese, chop cilantro, and slice avocado. In a small bowl, whisk together the sour cream and lime juice for a creamy topping.
Step 4: Warm Tostada Shells (Optional): If desired, you can quickly warm your store-bought tostada shells in a dry skillet over medium heat for 15-30 seconds per side for extra crispiness, or in the oven at 350°F (175°C) for 2-3 minutes. Alternatively, you can make your own: lightly brush corn tortillas with oil and bake at 375°F (190°C) for 8-10 minutes, flipping halfway, until golden and crisp. For frying, heat 1/2 inch of oil in a skillet, fry tortillas one at a time for 30 seconds per side until crisp, then drain on paper towels and season with salt.
Step 5: Assemble the Tostadas: To assemble each tostada, spread a thin layer of the lime sour cream mixture on the crispy tostada shell. Top generously with the seasoned shredded chicken.
Step 6: Add Toppings: Pile on your favorite fresh toppings: shredded lettuce, diced tomatoes, red onion, avocado slices (or guacamole), and a sprinkle of cotija cheese and fresh cilantro. Drizzle with extra lime sour cream or your favorite salsa if desired. Serve immediately and enjoy your easy chicken tostadas!