It depends on what you mean by "nearby." In your local neighborhood? Or just close to the same products and services you have, regardless of location?
If looking for competitors near your physical location, search for the product or service you offer, along with the city or area. That can be a very enlightening exercise to see who ranks with Google in your town.
If it's just by industry, product or service, type that industry, product, or service in the search and see what comes up. That, too, can be interesting to see who ranks in Google's eyes. Try several related terms. Look for businesses that are very similar to yours in terms of size and scope.
Also, if you are selling a product or service, doing searches on sites such as Amazon, Fiverr, etc. can also be a way to find out what and who is available in the market.
Searching on the Internet is truly the most efficient way to see what you're up against in the marketplace. Good luck with your business!