For Chainmail we recommend flat smooth jaw pliers. Only for very tough materials, such as large gauge Stainless should you use pliers with teeth. (Teeth tend to scratch, scar, and generally damage softer metals.)
Wide, flat nose pliers are best for larger gauge and interior diameter rings. The size of your pliers is always personal preference; larger hands will always benefit from larger pliers and smaller hands will always benefit from smaller pliers, etc. These Flat Nose Pliers are best for armour size jump rings of perhaps 18 gauge and larger and with an interior diameter of 1/4" and larger. You will need one pair for each hand in order to make chainmail.