Preheat oven to 350 degrees. Line a rimmed baking sheet with foil.
CHICKEN: In a small bowl, combine garlic powder, onion powder, chili powder, cumin, salt and pepper. Sprinkle seasoning on both sides of the chicken breasts. Bake chicken on prepared baking sheet for 20-25 minutes or until chicken is cooked through.
While the chicken cooks, prepare pico de gallo and guacamole.
PICO DE GALLO: Place all ingredients into a small bowl, stir to combine. Refrigerate until ready to use.
GUACAMOLE: Slice the avocados in half, removed the pit and skin and place in a mixing bowl. Mash the avocado with a fork and make it as chunky or smooth as you’d like. Add the remaining ingredients and stir together. Cover and refrigerate until ready to use.
Remove chicken from the oven and shred with 2 forks. Place the shredded chicken in a bowl and toss with 1 tablespoon lime juice and 2 teaspoons paprika.
Heat tostada shells according to package directions.
To Assemble: Spread guacamole across the tostada shell. Top with shredded chicken and pico de gallo.