If they've said that a condition of your place on the nursing course is "providing I pass my first year of my degree" and you don't pass the first year of your degree, then you won't have met the conditions of the offer.
That doesn't necessarily mean an automatic rejection, although it may do. It will depend on how many other offer-holders they have who have met all their offer conditions, and whether they still have space left on the course after confirming the place of those candidates.
How close to a pass do you think you might be? Assuming a pass is the standard 40%, you might have a better chance of being accepted if you just miss that (say, 38%) than if you clearly failed (say, 25%).