I'm sorry for your trouble - have you tried using the Dolphin browser instead of Chrome? It's free from either the Nook store or the Google Play store. It gives you the option to clear the cache when you exit, which helps to keeps the speed up.
The Google version also has a number or add-ons to hep you tailor Dolphin to suit your needs, and you may find one that helps with zooming text.
I use Dolphin regularly and just don't get pop up ads at all.