This is very good question, this is mainly for Nengcoin (NENG), not for Wrapped Nengcoin (WNENG).  The short answer is the new CPU and Mobile mining technology that never existed before Nengcoin offers this new 51% protection.  The 51% protection enhanced feature mainly come from CPU miners on PC/Mac/Chromebook or mobile CPU miners on android phone.

Please be aware that Nengcoin is a clone of litecoin,  but litecoin is mainly a ASIC mining coin.  Nengcoin is a scrypt coin, but mostly mined by ASIC miners, but controled by CPU miners on PC/phones.  Put this way, if 100% of CPU miners on NENG protect and or strike for a day with no CPU mining (this is not very likely case, just hypothetical case),  NENG blockchain most likely will be frozen, shut down, no matter how many ASIC try and mine with tons of hash rate throwing at NENG, it will most likely be shut down.  That is why this coin is CPU/mobile mining centered coin even though majority of mining profit goes to ASICs on scrypt.

For details of this works on tech level, checkout the v1.5.x branch upgrade pdf report above. That report can be served as technical white paper for Nengcoin.