I've 529 in two states, OH (R) and IL(NR), taken distribution from both for tuition. Whether the IL earning portion of distribution is taxable in OH &/or vice versa?

[Hal_Al]

It depends of where you live.  If you are an OH resident, any part of  both distributions, that is taxable on the federal return is also taxable on the OH return.  If you are not an OH resident, neither distribution is taxable on the OH return.