Locking a password manager and your computer is certainly good enough in many cases. But gaining access to memory might not need the sophistication of using nit

Locking a password manager and your computer is certainly good enough in many cases. But gaining access to memory might not need the sophistication of using nitrogen (see eg https://en.m.wikipedia.org/wiki/DMA_attack https://en.m.wikipedia.org/wiki/DMA_attack).