A friend opened a Nevis LLC and before settling for a bank outside of Nevis was approved for an account at IMBL.. Monthly fees were very high as of 2022, something like $200-250 per month. Will ask if he has more details. He was moving only a few hundred thousand USD and didn't see a reason to pay the fees when there were cheaper alternatives in St. Lucia and Belize which I assume have worked out.
The bank is apparently a subsidiary of the Nigerian state-owned bank of the same name. Based on what he said it struck me as a shady bank but I would also be curious to know more if anyone has tried them out.