Brianna Edwards tried to keep the Friars close, scoring all 10 of her points in the first half. But when she picked up her third foul, with just under 4 minutes to go in the half, Notre Dame was already up 19, 46-27.
Diggins had 17 points before intermission and McBride had 16 as the Irish went into the half leading 52-32.
Diggins also had two steals, moving her past assistant coach Niele Ivey and into the top spot on the school's career list with 349.
A win Monday would give the Irish the top seed in the Big East tournament. A loss to UConn would drop Notre Dame into a tie with the Huskies, and UConn would get the top seed in a tiebreaker, because the Huskies beat Marquette twice this season while Notre Dame was only 1-0 against the Golden Eagles.
The Irish have turned the rivalry with UConn into a one-sided affair lately, winning five of the past six meetings, including a 73-72 win at Connecticut on Jan. 5.
"Monday it will be to win the Big East outright, so we want to play well, because that looks good on our resume," Diggins said.
The Fighting Irish have never lost to Providence, improving to 22-0 with Saturday's win. Nineteen of those wins have come by double digits. Notre Dame also beat Providence at home this year, 89-44 in January, a game in which Diggins became the fourth Fighting Irish player to ever score 2,000 career points.
This was the final home game for Roberts, who last week scored her 1,000th career point, Edwards and Jenna Roncarati.
Tori Rule chipped in 13 points for the Friars.
Robinson Fruchtl, whose team lost to UConn earlier this season 105-49, said she'd give the slight edge Monday to Notre Dame, because the Irish have Diggins and UConn doesn't.
"She's the best point guard in the country in my opinion," she said. "Yes, she has great ability, but it's her leadership, it's her dictating the tempo, it's her getting people in the right spots."