My son is one year old he has flu can I put my milk in his nose?

What do you expect? Breast milk has many wonderful qualities ascribed to it, but it is not a panacea.It provides great nutrition as you have already known. The tired and true treatment for nasal congestion in infants is the put saline nose drops in the nostril, then suction it out with a rubber bulb syringe or a nosefrida ( to make him comfortable until he gets over his virus on his own.Hydrate also.
Not if U want it btr. If you put your milk in his nose it will trigger a foreign irritant reaction and lead to internal swelling and more congestion. There are many myths espoused by breast feeding supporters and this sounds like one.The only place breast milk does any good is when consumed.