For the marinade: In a mixing bowl, combine the olive oil, vinegar, Italian seasoning, garlic powder, and whisk to combine. Add the boneless skinless chicken breasts to the bowl, cover, and refrigerate for 4-6 hours or overnight, turning occasionally.
For the Chipotle BBQ sauce: In a small food processor or a jar using an immersion blender, combine the entire can of chipotles with adobo sauce, tequila, lime juice, garlic, and brown sugar, and blend until smooth.
*Note – If you do not want to use tequila, you can substitute chicken stock in its place.
In a small skillet over medium-high heat, pour the blended Chipotle BBQ sauce into the skillet and cook until the sauce begins to thicken, 5-10 minutes. If you’re ready to grill, you can use immediately or refrigerate until ready to grill.
Preheat the grill to 400 degrees Fahrenheit, and place the marinated chicken breasts smooth side down. Grill until the edges whiten and the chicken feels firm when pressed with tongs.
Flip the chicken and brush your desired amount of chipotle BBQ sauce on the cooked side of the chicken. Grill until the chicken is fully cooked and firm.
Remove chicken and serve with extra chipotle sauce on the side.