How can one reset Arduino Nano from NodeMCU?
Yes, you can reset a 5 V Arduino with esp8266. I did it many times. The esp8266 doesn't have a problem with pull-up level current at 5 V. 

On my picture io 0 of the esp-12F is wired to reset pin of Nano. The esp-12F runs WiFiLink firmware which can OTA upload sketch to ATmega328p and of course before flashing it must reset the ATmega.