Chung made the announcement Thursday in Seoul.
The parade was carried live by state TV for the first time, allowing North Koreans and the rest of the world to have a good look at the future leader. He also met with North Korean leader Kim Jong Un.
Kim got to the bargaining table in part by vowing not to resume nuclear tests, and he could use peace talks to legitimize his regime and get worldwide sanctions relaxed. He said Kim confirmed his commitment to the complete denuclearization of the Korean Peninsula.
Still, analysts at 38 North, a website devoted to "informed analysis of events in and around" North Korea, say satellite images ahead of the event show the largest number of shelters in the heavy equipment storage area ahead of any parade since Kim Jong Un rose to power.
Trump tweeted his thanks in response to the relayed statement of confidence.
The official said that there remained concerns that Kim's improved relationship with China and his planned summit with South Korean President Moon Jae-in this month could encourage him in resisting US demands. He reportedly expressed some frustration to Chung that measures he has taken thus far, including decommissioning a nuclear test site in May, have not been taken seriously by the United States.
North Korea feels it has already shown goodwill by not testing any missiles this year.
The State Department later said Pompeo was sending his newly appointed North Korea envoy, Stephen Biegun, to South Korea, China and Japan from September 10-15. They are believed to be those of American soldiers who died in the Korean War.
If it doesn't, it may be a sign Kim is serious about denuclearization.
US officials have previously said they have already made conciliatory gestures, such as halting joint military exercises with South Korea. North Koreans across the country have been mobilized for beautification efforts big and small, from filling potholes in rural roads to helping carry out major construction projects.
Cracks have started to develop in their relationship however, with a key visit to North Korea by USA secretary of state Mike Pompeo being cancelled last minute over "lack of progress".
However, negotiations have stalled as the United States pushes North Korea to make a full account of its nuclear program as a step toward denuclearization.
The spectacle, months in the making, will centre on a military parade and mass games predicted to put advanced missiles and leader Kim Jong-un's hopes for a stronger economy front and centre.
Senior statesman Kim Yong-nam, the head of North Korea's parliament, set the relatively softer tone for the event with an opening speech that emphasized the economic goals of the regime, not its nuclear might.
On Saturday, Li Zhanshu, the third-highest ranking official in the ruling Communist Party of China, flew into Pyongyang, while Valentina Matvienko, chairwoman of the Russian Federation Council, arrived in the capital on Friday.
He said, while China has listened to North Korea's concerns, the country has reduced trade with its neighbor and placed pressure on it.
President Trump has called on China to do more to get North Korea to take part in talks on denuclearization.
Director of National Intelligence Dan Coats told a conference in Washington on Tuesday that the US intelligence assessment of North Korea's nuclear intentions had not changed.
During his meeting with Kim, Chung delivered a message from Trump and will relay comments from Kim to U.S. National Security Advisor John Bolton, Moon's spokesman, Kim Eui-kyeom, told reporters.
Moon spoke to his aides Thursday about the next meeting with Kim.