Mix together mayonnaise, dijon mustard, and dill in a bowl and set aside.
Sprinkle the chicken with olive oil, garlic powder, onion powder, and a pinch of salt and pepper and rub them into the chicken.
Using a grill or grill pan on medium-high heat cook the chicken on both sides, about 6-8 minutes or until the chicken is cooked through and no longer pink inside. (using a thermometer the internal temperature should be 160 degrees.) (cooking time may vary depending upon the thickness of the chicken)
Slice the chicken.
Spread the mayo mixture on the roll. Top with tomato, lettuce, chicken, cheese, and avocado.