A few slices of cold pre-cooked chicken breast. Pure lean protein, no preparation, no smell from cooking.
Cold chicken has almost no smell, which matters when cooking smells trigger nausea. This is one of the best protein-per-calorie emergency foods.
Keep pre-cooked chicken strips or sliced deli chicken in the fridge. Rotisserie chicken pulled into strips also works.
Deli turkey is an equally good swap.