Easy Chicken Avocado Melt Sandwich (Crispy and Melty)

Ingredients

• 1/4 cup (60 g) mayonnaise
• 1 tablespoon fresh lime juice
• 1/2 teaspoon garlic powder
• 1/4 teaspoon smoked paprika
• 1/4 teaspoon kosher salt
• 1/8 teaspoon black pepper
• 8 slices sourdough bread
• 2 tablespoons softened butter, for the outside of the bread
• 2 cups (280 g) cooked chicken breast, shredded or thinly sliced
• 8 slices Monterey Jack cheese
• 4 slices sharp cheddar cheese
• 2 ripe avocados, sliced
• 1 tablespoon fresh lime juice, for the avocado
• Optional: sliced tomato, baby spinach, or pickled jalapenos