Place bacon slices, 4 at a time into a cold frying pan. Heat to medium-low and cook bacon, turning once until it has reached a deep brown color (about 10-15 minutes), remove from the pan and drain on paper towels.
Lightly grease the grates of an outdoor grill. Heat the grill to medium-high heat. Place chicken breasts onto the grill and cook while turning and brushing with the BBQ sauce frequently on
each side for 10-15 minutes per side (depending on the thickness), or until fully cooked (the internal temperature has reached 165 degrees). During the last few minutes of cooking top each chicken breast with 2 slices of bacon and shredded Colby-jack cheese.
Remove from the grill and top with green onions and tomatoes.