Even with Nougat's multitasking, Android is restrictive in the ways that apps can be placed on the screen. Flyperlink frees your browser so you can resize it however you want. Flyperlink has multiple ways to render webpages, but they are all centered around floating bubbles, sort of like Facebook chat heads. There's the full screen bubble, a Chrome custom tab, and the resizable popup.
You can also choose certain link types (eg. YouTube) that Flyperlink won't try to open. You can leave a page in the bubble, easily accessible at the edge of the screen while you do something else. It also includes a button to instantly send a link to your chosen backup browser in the event you need something more powerful. Flyperlink is free to try, but there are ads unless you upgrade to pro. That also enables popup mode.
Flyperlink (free, $0.99 in-app upgrade)