Saline nasal drop and steaming will work...See your doc as baby is small.

check whether nose is blocked or not. incase baby is breathing through mouth, u can give him nasoclear drops as suggested by my pediatric. also, try to apply ghee mix with vicks on his back and give him massage. my father in law suggested this thing. dont apply vicks on his nose. it will irritate him badly. make sure your baby wear woollen cloths from head to toe and cap is must in this season. consult your doctor fir medicines.

You can put nasoclear before feeding.

Please Consult a doc the baby is small

Steaming should be done carefully. You can turn on hot water tap and open ur child clothes and sit in the bathroom with your child so he gets steam indirectly.