Nicknames come from different places and different things. For example, the nickname Minutemen comes from Lexington. People call the minute men, minute men because they were to be ready in a minute's notice.
Along with Redcoats come from the British. People call the redcoats redcoats because they wear redcoats
Back then, the nicknames meant different things then they do now . As writing this, I am a Loyalist for our class debate. The nickname Loyalist came from the king because they we're so loyal to him. Molly Pitcher was a nickname for Mary Mccauley or Mary Hayes. They called her Mary Pitcher because Molly is another name for Mary and Pitcher because durring the war,she brought water in a pitcher to the men in the war.

Sources25253346GQDuPotdgs_th.jpga picture of the redcoats .
01.A day in the life of a colonial soldier