That would be an open question in every jurisdiction. There wasn't really a representation here, but it might be something more like the doctrine of "mistake". It's also not clear "your honor I never read the contract but my LLM told me it was okay to sign" is a great argument either. Doubly-true for your $1,500/hour law firm duped by something like this.

[Edit: by "nullify" you probably mean "void" or "voidable" which are remedies in equity, and the "never read it" argument carries even more burden there. As the citation notes the traditional remedy for contract issues is damages (i.e., cash payment).]