The Mediterranean diet is a very good diet for health, but can be expensive in the USA and isn't geared towards weight loss.
https://health.usnews.com/best-diet/mediterranean-diet
When you say "corn chips" most of them are high in sodium and fat.
Do you mean Fritos and Doritos Nacho, or do you mean a corn tortilla that's baked crunchy, or one that's deep-fried?
A one ounce, 28 gram serving of typical corn chips is 160 Calories, as about 10 grams of fat, 16 grams of carbs, and 2 grams protein.
Also gives you 160mg of sodium, and very little nutrition.
It's one of the salted fat-carb combination foods that particularly causes weight gain.
Fresh corn is on the acceptable list.
The diet is not extremely strict.
Corn is somewhat American. It's also becoming common to make ethanol, which is 39% of corn usage. It's not an easy question because the world is globalizing and Dorito's and Pringles and Kellogg's Corn flakes are in Saudi supermarkets. I think when they say "Mediterranean Diet" they mean the traditional one, rather than modern diets.
In any diet, small amounts of anything isn't a killer, but I'd be cautious about too many corn chips. I know tacos are going global now.
Bread is intended as whole grain typically.
I took a screen clip from a supermarket ad in Greece, and found similar in Saudi Arabia. They sell corn chips now and nacho cheese dip.