I am getting the same issue with MO not being able to visit anything on Nexus. It displays the mod information okay but all links to Nexus just simply take me to the Downloads tab in MO. My default browser is set to Chrome as well...I have not reinstalled WIndows 8.1 so that may not be the issue. It's a small issue....and for my lazy self it just means a couple more seconds of manual finger work BUT would love to have that convenience back.