I've found Streets to be more of a mental thing than a physical challenge. For many, the physical aspects of an indiscreet and quiet camera shot from the hip helps to overcome the mental challenge of confronting stranger with a bazooka staring down their throats. If you can get into the right frame of mind, you can shoot Streets with anything. A seasoned Street photog should do well with the Nikon. If you are just starting out on "Street", then discretion may be the better part of valor, until you develop your Street Sense and thick skin.
I recommend an OM-D or GH3, both are smallish (compared to dSLR's), lighting quick focus with very good, photojournalistic acceptable, IQ. I don't think the difference in IQ between µ4/3, APS-C or FF for Street genre is significant. The OM-D is quiet (no mirror slap), but the GH3 can be even silent with it's electronic shutter mode. The electronic shutter does work well with moving objects, long lenses, long exposures, et cetera. So if you're interested in the Silent/Electronic shutter aspects of the GH3 do your homework and see if it will work for you.
If you are a new into Streets, then check out Ray's gallery. Ray has captured some some wonderful images, pure Americana. Some quick tips (assuming you are neophyte), Shoot and walk, shoot and walk, shoot and walk. I like to capture the street moment, typically if you ask permission the moment is now theatre. So just shoot and walk. If someone yells at you, just keep on walking. After a while you'll develop a sixth sense of who you can openly shoot and who you need to be stealthy, who you can talk with and who is the last person in the world to you want to talk with. What has worked for me was to look and act professional. My cameras are in the open and I shoot with EVF. I like the challenge of the using the EVF over a stealthy mode of looking like a tourist (LCD) or shooting from the hip/belly. My typical set-up is one camera with a long lens the other wide. I dress 'professionally', long pants, collared shirts, closed-toed shoes. Most of the people on the streets are busy doing something, I try to fit into a mind set that they're working and so am I. That what work's for me, everyone is different, YMMV.
Good Luck and Good Shooting,
Gary
PS- If you want small, the GX1 is a pretty good deal w/a removable EVF. With a pancake, it is easily stuffed into a jacket pocket.
G