I saw this article on DxO’s support site (see https://support.dxo.com/hc/en-us/articles/4850558697245-Do-you-support-Capture-One-) that says “Many Capture One users successfully use it with Nik Collection” – but doesn’t say how.
Elsewhere I saw this description of how to set up Capture One to use the Nik Collection as an “external editor” (which is essentially what happens with Lightroom, though Nik sets that up automatically during installation and officially supports it). I don’t know if the information is current or accurate and of course can’t try it since I don’t have Capture One. But here it is:
And there is a post on this forum that (near the bottom) describes how to set it up for Windows, but may be adaptable to a Mac installation, at Add native Nik support for Capture One Pro - #12 by WitheringtonM.
If Capture One has a customer forum, you might also check there. If it’s possible, then SOMEONE has probably figured it out.
Regards,
Dale