Nashua is more of a hike. Try Salem, Windham, or Pelham, NH - they're right on 93, within a few exits of MA. If you find yourself working in the Merrimack Valley (Lawrence, Methuen, Haverhill, Andover) or along the 93 corridor (Billerica, Woburn, Wakefield, Reading, Stoneham) you will find that if you leave at the right time of day from NH, you will get there in minutes. Working closer to Boston (Boston proper, Cambridge, Chelsea, Medford, Malden, etc.) would take about 25-35 minutes with no traffic from the NH border (Salem). From Nashua, also with no traffic, you're looking at 45 minutes - still not bad, but you're using route 3 and 95 instead of 93 the whole way. That whole 4 hour thing I mentioned was worst case - you left your house at 8:15am and 93 was a parking lot. If you left an hour earlier you'd be at work, looking out the window at the highway, laughing at the folks stuck in traffic. That's how it is around there. (I know, I used to work right on 95 in Waltham).
As far as the nicest places to live in SNH, well, that's all up to what you want. If you are looking for a rural area, you've got to look. They exist - parts of Pelham, for example, have acreage available (last I saw). For the most part, though, it's all going to be developments and suburban neighborhoods, with expensive land and sized to match houses. For example, my mom's house is in Methuen, in one of the better school districts (brand new k-8 school... one of several). She's on just under an acre, with a little over 2k sf. Last I heard, her house was appraised at close to 600k. That same house on 10 acres down here in central VA would go for 250k, I'm sure.