Pat the chicken breasts dry. Season both sides with 1 teaspoon garlic powder, 1 teaspoon seasoned salt, and 1/2 teaspoon black pepper, then refrigerate until ready to grill.
Add the chipotle peppers (1/2 of a 7-oz can), 1 teaspoon garlic powder, and 4–5 drops of liquid smoke to the bowl of a food processor.
With the food processor running, slowly stream in 1/4 cup vegetable or canola oil and 1 cup melted butter until the mixture is smooth and emulsified; set the chipotle sauce aside.
Preheat and oil the grill (or grill pan). Grill the seasoned chicken breasts 9–12 minutes, turning once, until an instant-read thermometer reads 165°F (74°C).
Brush both sides of the cooked chicken with the prepared chipotle-butter sauce and cook for an additional minute per side to set the glaze.
Remove the chicken from the grill, let rest a few minutes, then slice into strips and serve in tortillas or as desired.