Student or Learner
"They stand a good chance of winning the game."
"They stand a good chance of losing the game."
Is the second sentence acceptable standard English?
Welcome to Using English.
Yes, both are fine.
Thank you for giving your thread a meaningful title and using proper capitalization and punctuation.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.