My 11 month old is getting very congested at night we've tryed humitifers, steam everything is a nebuliser nessesary or should we bring him in?

An exam may help. Sounds like you have done most of the recommended things to this point. An exam can reveal nasal swelling, a sinus infection or other issue. Be prepaired to list all potential nasal irritants your baby is exposed to.Cleaning fumes/perfumes/smoke/etc all will make baby stuffy.
Yes. If baby is very uncomfortable with nasal congestion and you tried suction get consultation to chech him.