It will depend on the charger you are using. Middle rated Tesla charger does 250 KW. Generally, it's bad practice to completely discharge a pack so it should be avoided. Also, charging the last 15% of a pack is much slower than charging the part from 5 to 80%. 120 Miles should need about 40 KWh but maybe 30 KWh, depending on which Tesla you had. 40 KWH from a 250 KW charger will take about .16 of an hour, or about 10 minutes of charging. If you are driving a Tesla and tell it you are going to charge at a certain charger, it will precondition the battery on the way there so it is ready to take a charge as fast as possible. Chargers available with your existing range in mind will show up on the navigation screen, along with how many are in use and how many are available. Tapping one on the screen will set it as the destination and give you guidance for how to get there. Back up to the charger and plug in. The chargers know your car and will bill your card so there is no overhead associated with getting charged.
Of course, there are chargers and there are Tesla chargers. If you drive a Tesla, you get to use Tesla chargers, which are much more reliable and easy to make work.