Interim manager Van Nistelrooy motivated to help Manchester United in any way
The Dutchman is in temporary charge at Old Trafford after Erik ten Hag was sacked earlier this week following a terrible start to the season, with United in 14th place in the Premier League.
Van Nistelrooy oversaw a 5-2 win against Leicester in the League Cup on Wednesday as talks continue over the potential appointment of Sporting Lisbon coach Ruben Amorim.
Amorim has promised to clarify his future after the Portuguese champions play on Friday.
Former United striker Van Nistelrooy, who returned to the club in July as part of Ten Hag's refreshed background team, looks set to take charge against Chelsea and could even oversee the team until the upcoming international break.
"As an assistant, I came here to help the club forward, and I'm still very motivated to do so in any capacity as an assistant and now as an interim manager, and after that I go back to my assistant contract that I have here for this season and next," he told a pre-match press conference on Thursday.
"I'm very motivated to stay here and help the club forward. That's my absolute goal."
Amorim, if his appointment is confirmed, will likely bring in his own staff.
Asked if it is his expectation that he will remain as an assistant under the new United boss Van Nistelrooy, a former PSV Eindhoven manager, said: "We will see but it's a contract situation that I'm in, and my desire to help the club forward.
"So I can speak to you about my side of this story, and after that, when the new situation is occurring, when the new manager is signing and conversations take place, we have to see how things develop."
Van Nistelrooy, who was a player at United under Alex Ferguson from 2001 to 2006, said it was "difficult that Erik (ten Hag) had to leave.
"It was very disappointing, obviously with mixed feelings, but after that you have to switch the mindset to win because in the end there's 75,000 people waiting and celebrating, and millions watching at home.
"I think that's what we try to do and same for Sunday at least, then after that we'll see."