Is there any case law where a jury was instructed to find that a home was substandard and not a nuisance?

Had the jury been given the instructions in question, there is a strong probability they would have found the dwelling was substandard and consequently a nuisance. If the jury determined that the housing code violations in the dwelling "endangered the life, limb, health, property, safety or welfare ... of the occupants thereof," then the jury would have to find that the building was a nuisance. Thus the failure to give the instructions was prejudicial error. (Cf. Knight v. Hallsthammar, supra, 29 Cal.3d 46, 59, 171 Cal.Rptr. 707, 623 P.2d 268.)

Plaintiffs also contend the trial court should have given their proposed instruction No. 26 which provided: