Separate tenderloin from chicken breasts and place breasts between two layers of cellophane and pound to an even thickness.
To brine the chicken, combine ¼ cup kosher salt in in a large bowl of warm water and stir until most of the salt is absorbed. Add the chicken to the bowl allow them to sit in the mixture to brine for at least 30 minutes. Remove the chicken from the brine, rinse with cold water and pat dry with paper towels.
Preheat the grill to medium-high heat. If using wooden skewers, soak them in water for 15 minutes to prevent them from burning too quickly on the grill.
Slice chicken breasts lengthwise into 1½-inch slices and thread evenly onto the skewers.
Sprinkle salt, pepper, and garlic powder over chicken skewers.
Combine melted butter with lime zest, lime juice, and chili powders and divide into two small bowls. Reserve one bowl for after cooking, and use the other to lightly brush chicken skewers with chili-lime butter.
Place the chicken skewers on the grill over medium-high heat. Cook for about 5 to 6 minutes, brush with chili-lime butter, turn and cook for another 5 to 6 minutes until the chicken is golden brown and cooked through.
Place chicken skewers on a clean plate and cover with aluminum foil. Let rest for about 5 minutes, then brush with reserved chili-lime butter and serve.