Arduino Nano and Voltage Pin

hello guys, i just wanna know, can Vin (pin 30) from arduino nano connected directly to the lipo battery with voltage 7.4v or 11.1v with 2650mAH or 3000mAH ?

according to "The Arduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27)"

the voltage is okay, but im not sure about the mAH value

Unless you are drawing large currents on some of the nano output pins, it should be fine. If you do draw more then what the battery can supply, then you'll notice funny behavior from your arduino. If this occurs, you could try using 2 or more batteries in parallel

Yes. The board will only draw the current it needs.