It appears that your hosta has some slug damage. If this is all the damage you have this late in the season, you are not doing too badly. (Do an online image search for hosta slug damage to see what we mean.) You can use a slug repellent but the growing season for hostas is just about over as you will probably have frost soon.
There are many different approaches to combating slugs. One is to go out every night after dark with a flashlight and pick them off. Another is to trap them with beer in a dish, however, some say this actually attracts more slugs! Others have good results sprinkling diatomaceous earth in a circle around each hosta. This winter would be a good time to do some research and choose one or more methods to try next spring.