Try it an see if he/she eats it. Usually, if they don't like the food, they spit it out. Bettas are fairly particular with food...
As for the nutritional benefits, the vast majority of foods are fine for fish. They are all formulated with vitamins, proteins, and minerals, which are what they need to live healthy lives.
That being said, again, bettas are picky eaters, and generally speaking the cheaper foods are generally less appetizing, and more utilitarian in nature. Try your food out though and see what happens. If he/she doesn't like it, you can try some tried and true foods that most people on here like... Betta Buffet by Omega One, and New Life Spectrum betta formula.