I am in the tombs and must fight Tanova, but she stays inside her little bubble and I can't seem to pop her pipe dream!
Any advice would be helpful!

Have you tried magic breaking spells like secret word, breach, pierce magic...? you should always have some of these memorized

In combination with what Ertai suggested, try summoning an air elemental and hang back and let it knock her down a few points. If you can summon more than one, you can really damage her and then simply clean up what's left of her!