Nicole Richie might credit her six month old daughter Harlow for saving her life, but she hasn’t changed her ways entirely. Richie is said to have been involved in an argument with another woman waiting in the valet line at the Hard Rock Hotel in Las Vegas on Saturday. Things got so heated that security escorted Richie out. Nicole’s rep says that nothing happened, though:

We’re told Nicole was involved in an altercation around 1 AM this morning [Sunday, July 6] with a female while in line at the valet outside the Hard Rock Hotel in Las Vegas. Sources say Richie was so rowdy she had to be escorted off the property by security!

The photo was taken early last night at Wasted Space inside the Hard Rock, where we’re told Nicole was partying with Carey Hart and the boys from Good Charlotte.

Hard Rock was mum on the issue.

UPDATE: Nicole’s rep sent us this statement: “She was in Vegas but there wasn’t an altercation of any kind involving her.”

[From TMZ]

You could see Richie arguing with someone. She doesn’t have the best reputation when it comes to getting along with people, particularly other women. She was probably wasted, but that would likely take about three drinks in a two hour period given how little she is. As long as she wasn’t drinking and driving it doesn’t seem like that big of a deal. She looks much more sober in these photos than Christina Aguilera did partying in Vegas a month ago.

Thanks to WENN for these photos of Richie on Saturday night.