The Crystal Palace man is back to full fitness.
Williams is, of course, a player full of pedigree. He was a star in the Palace side as a teenager and even won caps for Wales.
Recently however the 22-year-old has had to battle through some serious injury problems.
In 2011 he broke his leg playing for the Welsh Under-21 side and he has been battling several fitness issues ever since – including a long-standing groin problem.
Williams is now fully fit and featured for Wales in their recent 2-0 win against Andorra. He has been speaking to the Crystal Palace website about his return to fitness for his nation, and reveled what he will be avoiding in the future:
"For moments like this, it's worth it.
"It was quite emotional at the end, just to be fit again is great. I'm happy, I'll stay clear of nasty challenges and I should be all right.
"I had to pinch myself a bit and say 'Jonny calm down,' it was my first start in 12 months and it was a big occasion.
"I just wanted to come off the pitch fit and I am, so that's [made tonight] even more special for me."
Of course Williams' long-term future lies with Crystal Palace but in the short-term he will be hoping to make more of an impact at Forest during his loan spell.
Fans of the club will not be keen on him ducking out of challenges but his competitive attitude is likely to make that impossible anyway.
He has so far played just 15 minutes for the club, coming on in a 2-1 defeat to Middlesbrough and will hope his recent 86 minute display for Wales books him a place in the Forest first-team going forward.