The former Pussycat Doll also revealed that she is still in touch with the N-Dubz singer, who has been at the centre of controversy in recent months, following her arrest on suspicion of supplying class A drugs.
Asked if she missed working with Tulisa, Nicole told reporters including HuffPost UK at the first arena auditions: "I mean, it was her choice and I'm happy for her and I always wish her the best - me and Tulisa still keep in touch.
"It was an honour to be on the panel with her," she added.
Louis Walsh - who has been reunited with former judge Sharon Osbourne, after she returned in Tulisa's place - also echoed Nicole's thoughts, adding: "I'd like Tulisa back. I love her, she's great. What you see is what you get with Tuilsa, there's nothing phoney.
"I think if Sharon had another daughter, it would be Tulisa," he laughed.