This is a strange rumor, which could explain Samsung's quick exit from several markets.
After years of producing half-baked, mediocre photographic equipment, Samsung has produced desirable equipment, precisely, the NX1.
It has a 28 MP sensor, which is a new density for APS-C, which has been held to 24 MP for a while, equivalent to the 16 MP for (micro) Four-Thirds. Apparently, the image quality has been impressive and the video is equally impressive, using H.265, rather than H.264.
I don't care for Samsung. For years, they have produced products that were not complete. They left buggy firmware in place while introducing products to replace those unfinished products. This NX1 wasn't so different. They introduced the body in almost a beta test state. Almost daily, they were providing firmware updates and now, it's very, very good--desirable.
Unfortunately, the rest of the NX-system is not worthy, which is why this rumor is so interesting.
Obviously, Nikon has a great APS-C presence in the industry. I even bought a D7200 recently. What if the emotional successor to the D300 could be based on the technology of the NX1? I keep seeing the D400 pop up in rumors but no body.
If Nikon called for third parties to supply lenses for APS-C mirror-less bodies, they could certainly move the market more than FujiFilm, even though FujiFilm is very dedicated. Sony barely has had an impact and Samsung seemed to drag down the market.
What would be even more interesting is a 135 Format/FX sized sensor based on Samsung's technology. Could the D810 suddenly be supplanted? Could Sony be removed as a sensor supplier to Nikon?
I wonder if the sensor technology is a one-hit-wonder type of success. If it moves Nikon into the mirror-less market, it could really change the market and scare the stuffing out of Canon.
Update 2015.12.04: The denial from Samsung tends to dismiss a full sale but seems to suggest that a cooperative use of the technology is possible. I still don't believe that Samsung's NX mount would be used, even though this would provide a few lenses. It is more likely that Nikon would want to create a mount, so that they can control everything about it. Obviously, if they're interesting in APS-C, they've run out of room between CX and DX but they're likely more interested in pushing Sony out of the market than handling the markets of micro Four-Thirds or FujiFilm.
I'm thinking that this move is similar to the move where Apple meant to split their relationship with Samsung, as they didn't trust Samsung not to use their processor design enhancements and went to TSMC for manufacturing.
2015.12.13: You have to wonder if the D610 could be the first to be replaced and there is no D300/D300s replacement at all, but a Sony A7 Mk II-type 135 Format body.