Has this happened to your Spektrum transmitter?
It happened to mine and I couldn’t find the missing nut. After sending an e-mail to Horizon Hobbies I got a response listing the web page for eight replacement nuts and a tightening tool.
They even have orange colored nuts if you want to jazz up your Tx….
Cheers,
Jeff Struthers
https://www.horizonhobby.com/product/radio-silver-switch-nuts-8-and-wrench/SPMA1304.html
https://www.horizonhobby.com/product/radio-orange-switch-nuts-8-and-wrench/SPMA1303.html