Yes as noted already by now, Oak Street Beach. Off of Division. Crowded though.
NYC and Chicago are very different and both quite different than other cities as well.
You want the Manhattan experience the only place to get it is Manhattan. You already know what that is.
Chicago is the next closest in the United States to that urban concentration (LA is larger in population but not an urban experience at all) but it is a big jump. Bigger though than Seattle, SF, and Boston.
Chicago is prettier. The architecture more significant and not so packed that you cannot appreciate the skyline. Not anywhere near as crowded and much more manageable to know where you are (“the lake is always east”). Must-do items as a visitor: both a river architecture tour and a walking one; Cloud Gate (“The Bean”) and its environs; Maggie Daly Park; The Art Institute (especially if you are fan of Impressionism). Rent a bike (Divvy stations all over the place) and ride around; it is much more bike friendly than NYC and not just the lakefront path. I wouldn’t recommend Navy Pier other than to know what it is and maybe for the view from the big Ferris wheel. Experiencing a game at Wrigley is worth it even if the Cubs weren’t good. The Cell (where the Sox play) not so much.
If you are an architecture buff then take an el ride out to Oak Park and go on a Frank Lloyd Wright tour too.
Yeah the safety comments made are ignorant. It is a huge problem heavily concentrated in a few neighborhoods none of which are close to where you are.