Broughton bowled with great pace and accuracy to finish with excellent figures of 5-16 from ten overs to help bowl the visitors out for just 45.
Tom Hackett took the first three wickets of the innings to take apart the Heighington top order.
Rich Hickling then took the final wicket to end the innings and reach 30 league wickets for the season.
Openers Rob Bee (25*) and Fraser Pemberton (22*) knocked the runs off without any problem at all to secure a ten wicket victory and all 20 points.
This weekend the Sunday XI finish their league season with a trip to table-toppers North Scarle who are already confirmed as champions, while Horncastle have a top five place secured going into the last game.