Preheat convection oven to 325°F (conventional oven 350°F).
Place everything seasoning in a shallow dish. Rub chicken breasts with oil and then coat them in the everything seasoning, being sure to stir the seasoning between each coating to ensure even amount of each spice.
Place on a parchment lined sheet tray and bake until the chicken's internal temperature is 165°F. Allow chicken to rest for 10 minutes before slicing.
To build the sandwich, spread 1 tablespoon of the Everything Dip on both the base and crown of the roll. Place 4 oz of sliced chicken breast on the base of the roll. Top with tomato, onion, and spinach. Finish build with the crown of the roll. Serve warm.