NanoCell and QLED are two technologies that promise to improve the picture quality of a smart TV. NanoCell is only present in LG TVs, while QLED was invented by Sony, but was commercially adopted by Samsung, which also manufactures such panels for other brands. In general, both technologies are technically very similar, making the choice between them quite meticulous. Both, however, are cheaper alternatives to OLED TVs, a more modern type of television that can reproduce even more faithful colors by using a composition of emitter diodes instead of backlighting.
See below the differences and similarities between NanoCell and QLED technologies. Also, see how they can improve the picture on a 4K TV.