McKinnon converted 7 of 9 field goal attempts in the first half to help the Nor'easters (2-0) to a 29-17 advantage.
UNE's defense limited the Engineers to 31 percent (13 of 42) shooting from the floor for the game, while MIT turned the ball over 24 times.
First-year forward Kate Bailey (Searsmont, Maine) had nine points and was named to the all-tournament team.
First-year Christa Margossian (Revere, Mass.) had 13 points and eight rebounds for MIT, which fell to 1-1.
The Nor'easters return to action on Tuesday at 6:00 p.m. when they host Bowdoin College, the country's top-ranked team and last season's national runner-up.