According to the official Korea Central News Agency(KCNA) Kim and Chinese President Hu Jintao agreed to push for "a negotiated peaceful solution to the issue".
Six nation talks, hosted by Beijing, have been on hold since November when North Korea demanded that the US lift financial sanctions imposed on it.
According to KCNA: "He [Kim] pointed out that the DPRK [North Korea] would join Chinese comrades in the efforts to seek a way of overcoming the difficulties lying in the way of the six-party talks and steadily advance the talks."
In response, Hu reaffirmed China's support for the dialogue which involves the US, Russia, South Korea and Japan.
"He [Hu] pointed out that the Chinese side is ready to ... put spurs to the six-party talks so that they may make steady progress," the report said.
After a week-long Chinese media blackout the state Xinhua news agency confirmed Kim's eight-day visit, which took him to the central province of Hubei and the booming southern province of Guangdong as well as Beijing.
"[Kim Jong-Il] pointed out that the DPRK (North Korea) would join Chinese comrades...in the way of the six-party talks and steadily advance the talks"
Meanwhile, Christopher Hill, the US envoy on North Korea's nuclear programme met Chinese officials on Wednesday and news reports said he also had a meeting with his North Korean counterpart to discuss reviving six-nation disarmament talks.
According to South Korea's Yonhap News Agency, Hill held a meeting in Beijing's state guesthouse with his North Korean counterpart Kim Kye Gwan. The talks were mediated by Wu Dawei, the Chinese vice-foreign minister, Yonhap said.
The flurry of diplomatic contacts, coming on the heels of Kim's visit, raised hopes of jump-starting the stalled discussions.
The American envoy, who is an assistant US secretary of state, said he had good discussions with Chinese officials but made no mention of a possible meeting with North Korean envoys.
Hill also visited Beijing last week as reports emerged that Kim had arrived in the country. But the American envoy said the timing of the two trips was coincidental and that he had no plans to meet Kim.
Aside from visiting Beijing, KCNA reported that Kim had toured a series of southern Chinese cities regarded as incubators of economic reforms, and praised Beijing's policies - a possible indication he was seeking tips on measures to revitalise the North's stagnant economy.
During his tour of Wuhan, Yichang, Guangzhou, Zhuhai and Shenzhen, Kim visited enterprises and institutes in the fields of industry, agriculture, science and technology, and education.
The trip was conducted in secrecy and amid tight security, with even China refusing to confirm Kim's presence during his time there.
Chinese President Hu held talks
with Kim on the nuclear issue
KCNA said Kim was in China on an unofficial visit from 10 January through to Wednesday at Hu's invitation.
A train believed to be carrying Kim crossed into North Korea at about 10am (0100 GMT)on Wednesday after a 20-minute stop at the Chinese border city of Dandong, South Korea's Yonhap agency reported.