Two members have pointed out good possibilities. The D3200 may be front or back focusing. Unfortunately, the D3200 doesn't have AF fine tuning. You might still check if it is front or back focusing. If you're using the .jpeg files out of the camera, then the picture controls are applied. Nikon sets the default sharpening for the picture controls very low. Go through all of them - vivid, standard, neutral, monochrome, and others and boost the sharpening to level 6.

There are so may possibilities why your photos are not sharp. Can you take some test photos of the same subject with both cameras and post them? Be sure to check the "Store Original" box.

In the Sony world there are various free softwares for remote viewing and camera control available on their website. Which one to use varies with the model of Sony camera. Although the User Interface is a bit clunky, With a long USB cord, I can, from a distance, view on my laptop what my cameras is seeing and take the photo when the image is right. I can set up my camera on a tripod close to a perch and allow the birds to become accustomed to it without having to be at the camera myself (Thus not spooking the birds or changing their behavior). Sometimes the birds even land on my camera. With my telephoto zoom, I can get in tight enough to get just a goldfinch's head in the frame.
On a chilly day I can set up my gear outside and sit inside with my laptop where it's warm. It's the ultimate photo blind. I have no problem with a 50 ft USB cord but adding a second 50 ft USB extension is too long (or the extension USB cord is faulty)
It's likely that other manufacturers websites also offer free software downloads that accomplish the same thing (tethering). It's likely that Nikon has downloadable software for your computer that will allow your 3100 to do what my Sonys will do.