Can anyone give some tips on beating this level?

Sure I can offer some assistance

The tactic I used for the chess board was sort of lure and kill. Remember its much easier to kill one than kill 5 or 6 opponents. I had my mage equipped with a few nice magic wands and my fighters using range attack.... then I move all my party to the bottom right hand corner of the chessboard. Once there, I take a (strong) scout inch by inch forward until one opponent see's and attacks me. note that only one opponent should see you where possible. keep doing this until all are gone. Hint: save after killing each one good luck, hope this helps.

regards
Tristan

In my case, I simply cast Cloud Kill at the central region of the chess board and multiple Fireballs after that. With Dynaheir at 9th lvl, this tatic effectively took out all of the King's horses (except for 1 seriously weakened Knight) and men and left the King severely weakened. No traps were triggered and the casualty rate was 0.

Yeh, I agree. The best way I found was to send one, two or more fireballs down towards the far end of the board. Whatever survives then comes down at you ready to be pummelled by arrows or more spells. A haste spell is also a good idea but you might need to go back to a save game just before the board else the party will be spread out too far.

Good luck.

Thank you for the help! I did beat it.