Things that taste great are tasty. You could describe your favorite foods, from doughnuts to baked ziti, as tasty.
While tasty basically means the same thing as yummy or flavorful, it implies a less serious compliment than the word delicious, for example. Potato chips are tasty, and so are grilled cheese sandwiches and soft serve ice cream cones. They're pleasant and appetizing, but not necessarily the most amazing food you've ever eaten. Tasty once had a secondary meaning of "elegant" or "tasteful."