If you want to play several games at once against your students, or maybe you just want to challenge yourself with multiple games at once, if you are a premium member, you can do this at Chess.com! Here is Danny Rensch explaining how:
To play multiple games at once, you must be in live chess: https://www.chess.com/live
Click on the options gear icon at the top right of the chess board:
In the next menu, click on the 'play' tab, then the 'Live' tab, and then toggle the switch for multiple games, and auto switch game:
When auto switch is on, after each move you will automatically be taken to the next game where it is your turn with the least time remaining. This option will not prevent you from manually switching between games as well.
Once these options are both turned on, you will be able to accept multiple challenges from all your students or friends!
Open games window
Whether playing or watching multiple games, you can also use the Open Games window. Press . (period key) on your keyboard to open a window showing all your current open games, games you are either watching or playing:
Click on any of the games listed in this window to instantly switch to that game, without going to a new tab.