Smith potted the rebound of an Alexei Emelin point blast at 1:26 and then beat goalie Anton Khudobin at 19:42, taking Mattias Ekholm's pass and lofting a wrister for his 11th goal. In 78 games last season, Smith scored just 12 goals.
Khudobin (7-1-2), who entered the night with a 2.22 goals-against average and a .932 save percentage, was run out of the crease after allowing two more goals in the first 4:10 of the second period. Nick Bonino got to a rebound and poked it inside the left post at 2:15, followed by Kevin Fiala undressing Khudobin before scoring on a backhander less than two minutes later.
Boston (12-9-4) made a game of it by scoring the next three goals. Charlie McAvoy's one-timer on the power play got it on the board at 10:14 of the second period.
Zdeno Chara's wrister from the point at 4:33 of the third period made it 4-2, and David Pastrnak wired a wrister from the left circle at 5:48 to pull the Bruins within a goal.
After a timeout by coach Peter Laviolette, Nashville (17-7-3) responded at 6:22 of the third period. Roman Josi sent Filip Forsberg in on a breakaway, and Forsberg beat goalie Tuukka Rask to the glove side for his 14th goal. Forsberg has at least a point in all 14 home games this season.
Pekka Rinne (16-4-2) made 37 saves, none bigger than his stop of Pastrnak at the goalmouth in the game's first 40 seconds.
Khudobin made 10 saves on 14 shots, while Rask stopped 10 of 11 shots in relief.
The Predators didn't convert on either of their two power-play chances, the first time this season they had failed to net a man-advantage goal in 14 home games.
NOTES: Nashville C Ryan Johansen (upper-body injury) missed a game for the first time this season. He was hurt in the second period of a 3-2 shootout win over Anaheim on Saturday and didn't play the last 33-plus minutes that evening. ... Boston LW Jake DeBrusk (upper-body injury) missed his second game Monday night. DeBrusk tallied the go-ahead goal in his NHL debut against the Predators on Oct. 5. ... The Bruins scratched D Paul Postma, LW Matt Beleskey and C Frank Vatrano. ... Nashville scratched D Anthony Bitetto and LW Cody McLeod. D Yannick Weber (lower-body injury) drew back into the lineup after missing 10 games.