In a bowl mix the mayo and horseradish. Season with salt and pepper to taste.
Heat a nonstick pan on medium heat. Warm the naan rounds on both sides.
Spread the horseradish mayo on both halves of the naan rounds. Layer with a spring mix, roast beef, tomato, onion, and cheese.
Serve with chips.
Notes
Pro tips: Butterfly the chicken: Lay the breasts down on a cutting board, using a sharp knife parallel to the cutting board slice the breasts through the middle (carefully) all the way in half.