Tips on writing about a menu item

Hi,

I was looking at the TOGO's menu sheet and it had this for its Taco Salad.

Taco Salad

Crunchy tortilla chips covered with Togo's own chili. Topped with Cheddar cheese, shredded lettuce, tomatoes, pepperoncinis, avocado & sour cream. Served with a mild taco sauce.

Do you any tips on writing out the ingredients? I know some are variable nouns and some are not.

My basic understanding on this is that if you cannot count them, then list them in the uncountable form like chili, sauce and sour cream and if they possess the variable nature like avocado, lettuce, cheese, then you should write them in their uncountable form.

Also, is it 'mashed potato' or 'mashed potatoes'?

Sorry if my question is ambiguous.