Partially. The CIA controlled them but it was connected to the 90s and various issues which transferred a large amount of American tech to China through NK while making it appear like negotiations were taking place. Now since then and (speculation) probably about 2000-2005 it became fully under puppet control of China due to many factors while still more tech and data were being transferred to China.
So come ten years later China had a huge hand in every American facet of society and was even (still can't fucking believe this) building our key military and health related systems which is where they added their hardware backdoors which let them spy on everyone. NK, however, got to a point where it appeared Kim was trying to break away and kill off anyone who was controlled by China so he killed his brother the moment he arrived in China and various others in country. Obama allowed the islands to go up which gave them control of that area but also boxed NK in. Then Trump came in and opened dialogue with Kim in a serious way which would allow NK to break that control and give them a very stable and wealthy trade partner in the US. The POTUS wanted to completely dismantle the nuke program but he wanted to keep some.
Now the interesting thing is that many may conclude he wants to keep them for potential issues with the US when Trump's terms end. However, I personally believe that Kim wants to keep them not just for that potential issue but he also recognizes that China is clearly prepping for conflict which means expansion which means he will be on their list for either China to envelop that area/take his army for their needs OR a complete overhaul under their control so he may be of the desire to keep the nukes to keep them away as well.
Everything I have read about Kim and his history says he has a lot of distrust for that relationship north of him and considering his huge military assets in the north that speaks volumes that he does not trust them not to try to expand into his country. So Trump is trying to pull him away from them and create a long standing relationship which would be good for the US in that it ends potential nuclear war with them BUT just as important it cockblocks China from a massive army increase, a buffer state and an ally which would allow the US to have an easier time dismantling the shit Obama and Clinton allowed into the South Pacific.
A collective alliance of the US, Australia, NK, SK, Japan and Vietnam is very good and China will do everything to prevent that.