Can wearing earplugs to bed cause nasal and ear congestion in the morning?

Yes: Provided that the earplugs are standard and not some unusual design there should rarely be a problem. However, earplugs can push normal ear cerumen (wax) into the ear canal and cause blockage which will be sensed as ear congestion or decreased hearing ( known as conductive or mechanical hearing loss). The sense of nasal congestion should not be related to earplugs.