The 'American's Got Talent' host says he is "sad" about how the 27-year-old actress, who was recently charged with attempted evidence tampering, reckless endangerment and marijuana possession, has been living her life recently because he once considered her to be "like my little sister."
The 32-year-old star told Howard Stern on his radio show on Tuesday: "I worked on Amanda's show when she had her show. To see someone you'd seen at nine, running around with a snotty nose, and now to see her like that is like, 'Wow, man! That's sad.'"
Nick, who is married to Mariah Carey, said that he recently tried to get in touch with the former Nickelodeon star but was unable to reach her.
He said: "I tried to reach out."
The 'Easy A' actress, who has reportedly cut off all contact with her family and was accused of lunging at a male fan after he tried to take her photo last weekend, is preparing to have her third nose job in a few weeks.
After undergoing her first surgery last month, she revealed she plans to have further work done and is currently "in between nose surgeries."
She recently tweeted: "I'm in between nose surgeries! My eyes are black and blue because my nose is broken! I can't wait for my nose to be done!"
She also wrote on Tuesday: "I can't wait for my surgeries so I can start taking pictures!"