Help identifying a decapped IC chip
It's going to be very hard to determine with any great certainty, but I would suggest Texas Instruments MSP430FR5738 microcontroller as a possibility. Though it is questionable.
If you could provide further details/pictures of the board itself and get an idea of some of the connections/functionality that would help.

My reasoning:
The (m) appears to be the US standard copyright symbol for a set of IC masks - Ⓜ.  Thanks @SamGibson for pointing that out.
The first line - 2010TI - reads to me as a year, 2010, and then could suggest the company - TI would be Texas Instruments (This has been confirmed by @AlexanderStohr's answer).
That leaves NM5739, which doesn't match anything particularly sensible. But then to be honest I wouldn't expect it to, die numbering is generally entirely internal, and there is no reason to suspect it will match the actual part number. But lets assume that it does.
The only part that TI sells with a number containing 5739 is the MSP430 series of microcontrollers. You've tagged it with microcontroller, but that might just be bad tagging.
Of these, the 5739 series number is unfortunately not in the correct package - its a 40pin QFN. However, the 5738 is in a 24pin QFN package -- &quot;RGE&quot;. The RGE package is 4mm x 4mm and 6 pins on each side. That matches.
Now as far as I can tell, the only difference between a 5739 and a 5738 is the number of available IO pins. It stands to reason that TI might use the same die for both to save costs, and for the smaller packages simply not bother to wire out some of the pins. This is quite a common thing to do. And from your picture it appears that there are pads which are not pinned out, though perhaps the bonds may have been lost during decapitation (?).
Furthermore, the datasheet for this series was released June 2011. If we assume a period of development before hand, it stands to reason that 2010 would be an apt year for it.