There are many reports that I’ve confirmed on my copy of the Google/ Nik Collection. That it is no longer fully compatible with Photoshop Version CC 2017
On Google/Nik’s website it states “The Nik Collection is free and compatible with Mac OS X 10.7 through 10.10; Windows Vista, 7, 8; and Adobe Photoshop through CC 2015. We have no plans to update the Collection or add new features over time.”
Also note they say nothing about being compatible with Windows 10
If you can’t find your Nik collection iPlug ins ( Or any Plug-ins Photoshop CC2017 you need to make sure you move the Plug-ins to the new default folder location for Adobe.