Max current of Vin and 5V pin on Arduino Nano
It's hard to say. The maximum the on-board regulator can provide is 800mA. However the actual amount it can provide at any time depends on other external factors - most notably:


The voltage of your supply
The ambient temperature around the board
The thermal mass of the copper the tab is soldered to


The higher your input voltage the more excess voltage has to be converted to heat. When it gets too hot it overheats and (theoretically) shuts down.

Also the board itself will take some of the maximum 800mA quota, say 50mA (guestimate), so that leaves 750mA theoretical maximum for the 5V pin - but only when powered from not much more than 6.2V (5V + 1.2V regulator dropout voltage).

However, if you are powering from the USB port then it is limited to whatever the USB port can provide (100mA for a passive hub, 500mA for a normal USB port, 2A for a CDP).

The VIN current will be the same as the 5V pin current + the board current.