The nebulizer of choice for infants is a compressor based one with a mask. Some of the quieter ones are the smaller "travel" ones, placed as far from the child as tubing allows. We use Innova Traveler in our family. The trick is making it acceptable to child and caregiver - we use distraction - videos, screen time, reading aloud...with older infants, toddlers we use rewards for tolerating - stickers, treats...
Also, sometimes we do "blow-by" treatment or divide treatment time to make it work. Babies and kids are all different. The adult needs to be flexible, but stay in charge and make sure kids get the meds they need.
Sue