You seem to be further along in your Nimblett research than I am.
I've traced back to my 4G grandfather, Joseph Nimblet, who was born 1772, allegedly in Middleboro, Plymouth County, Mass. From there the trail goes kind of lukewarm. No land or probate records for Nimblets in Plymouth County. Only two vital records in Middleboro for Nimblets, both marriages of women whose ages and names make them likely candidates for sisters of Joseph, but that's about as far as I get. (I also have Joseph's marriage to his first wife, in Carver, Mass., but it does not offer information about earlier generations.)
I've been researching the Essex County Nimblets (the only others I have detected in Massachusetts in late 1700s) to see whether there is a connection, but have not found anything so far.
I would love to hear more about your Salem/Marblehead connections, to see whether that helps me.
Are you related to Robert Nimblet, of Marblehead? Do you know that he rowed Washington's army across the Delaware in the famous Revolutionary War crossing?