I need advice on how to bring home a baby to a small 13ish lb yorkie. He is a little aggressive…

I need advice on how to bring home a baby to a small 13ish lb yorkie. He is a little aggressive towards strangers. But I think he mostly is scared. He is very attached to me and my husband. He likes children. He Did try to bite my 11 yr old nephew after he provoked him. He sleeps in bed with us also. Just some advice please ladies.