You can still get a chronological feed if you tap the Instagram logo at the top and click "Following"

But you can't turn that mode on as a default, and it essentially kicks you from the normal app hierarchy into a separate barebones screen. I find it's all for naught anyway because my friends have long since stopped making regular posts on Instagram, it's more common to use stories.

Do Stories show up differently than posts? Asking as someone that has not used Instagram beyond looking at a few specific profiles.