Preheat a grill or grill pan on medium heat. Season the chicken breast with salt and pepper, and cook 6 - 7 minutes per side, turning once, until the center of the chicken breast is no longer pink and an internal temperature of 160 degrees is achieved. (time may vary depending on the thickness of the chicken breast, use a thermometer) Remove the chicken, and slice thin.
In a bowl combine the mayo, thyme leaves and chives.
Spread the herb mayonnaise on the wrap, place the tomatoes and season with salt and pepper. Layer with spinach, chicken, onion, and pepper jack cheese. Fold in the ends and roll up. Cut in half and serve with chips and pickles.