As a general rule, commercial indemnity insurers (or private health insurance companies) have a list of empaneled providers (typically only physicians) that insured members choose within their health care network. We're all familiar with that as individuals with our own health insurance coverage. However, these companies also make up their own rules in terms of reimbursement of services provided by independently licensed non-physician providers such as NP's and CNS's. There are 4 scenarios that happen depending on the particular company:
1. Payment at the same rate as physicians without a requirement for admission to a provider panel.
2. Payment at a reduced rate.
3. Payment under the physician's name.
4. Denial of payment.
What surprised me by the OP's post is that the location is Oregon, an independent practice state, where last year HB2902 was signed into law. This law (also called the Payment Parity Bill Law) mandates all insurance companies to reimburse NP's and PA's the same rate as physicians. This is the first ever law of its kind in the nation. Having said this, I am drawn to the conclusion that CNS's (though similar in role to NP's per the Oregon BON) are not really treated the same as NP's in Oregon. I think your best bet is to seek assistance with answers from Oregon's CNS association.
Source: HB 2902 :: Oregon Legislature Bill Tracker - Your Government - The Oregonian