From the Merriam-Webster Learner's Dictionary:
stand for (something)
3 : to allow (something) to continue to happen — usually used in negative statements
I will not stand for [=put up with] any more of this nonsense.
a : to be willing or able to accept (something or someone unpleasant) without complaint — usually used with can, can't, cannot, could, and couldn't
Can you stand [=tolerate, put up with] waiting a few more minutes? = Can you stand to wait a few more minutes?
How can you stand her friends?
He couldn't stand [=bear, endure] the pain.
So, in the dictionary, both "stand" and "stand for" means "put up with".
Are "I am not standing for your nonsense any longer" and "I am not standing your nonsense any longer" the same?
Is there any difference between them?