Marchand is on pace for 28 goals this season, if he keeps that pace he'll need 71 after this season.
That's not impossible, really depends upon how long he wants to/can keep playing. If he keeps playing till he's 45 like Chara did he's prolly a lock. If he retires at 40 he'd need 17 goals/season over the next four, which is very doable. If he maintains the 28-30 goals/season average he's been doing the past 6 years or so he can do it in a little over three.
But it's also very conceivable he falls short, so wouldn't be surprised either way. But if he next contract is 3 years he's prolly got a decent shot at least.