Even if Sununu wins reelection this year (which I’ll concede is at least a somewhat conceivable scenario, although I still doubt it happens), there is no way he’s winning a federal race in a state like this, especially against a popular incumbent Democratic Senator. Sorry, but governors' races ≠ Senate races, ESPECIALLY in New England. Shaheen and Hassan are both safe.
If Trump somehow pulls off re-election in 2020 or Pence magically gets elected of his own accord in 2020, I'll agree with you. Otherwise, no.