Ravlich said she knew the bag belonged to the store because of its distinctive bright colours and it had been out the back for about a week.
To be sure, Ravlich said she waited until Nash returned to the shop and "was deployed" downstairs to give her time to go look in her car.
And there it was, she said, jammed in a back footwell wrapped in what appeared to be a white towel.
"I could see it was in her car and I just felt sick," the manager told the court.
Devastated by the discovery, Ravlich quickly checked the shop's CCTV footage.
However, the USB stick with the CCTV footage was broken and by the time police went to get another copy, it had been wiped from the system.
But Nash said she rushed from the store because she her Range Rover, which she was still paying off, was parked in a 60-minute zone.
"I went, 'Ugh' and thought, 'Okay that's not good'."
So she threw her white jumper over her shoulder along with her black bag and went to move the car across the road.
Nash, supported by ex-husband Thane Kirby, told the court she'd bought the bright pink and yellow fake Dior bag about five or six years ago, along with two others, for her daughters to play dress-ups with.
In fact, Nash hadn't even seen the bag out the back that morning - she would have noticed and thought "that's like mine", she said.
Nash said she intended to sell a bunch of bags at a market in Silverdale but not the fake Dior bag as it was her daughter's play thing.
She has been remanded on bail and will be sentenced at a later date.
JUDGE MATHERS' DECISION
Judge Mathers said in her decision while there was no onus on Nash to prove her innocence she had to put up a "positive defence" to rebut the fact that an identical bag to the missing one was found in her car.
"I take into account it is very difficult to tell if a witness is lying but where there are such stark inconsistencies coupled with the bag allegedly being a play bag for her children for up to five years and yet being in 'mint' or 'very good' condition, despite describing her children as 'rambunctious and messy', and being dusty on top, and coupled with the explanation of an identical bag and the fact of no sale taking place, I found her evidence most unsatisfactory and unreliable that I have not accepted it."
The judge said a finding of theft was a very serious matter regardless of the small about at stake.
Therefore, Judge Mathers gave the matter "anxious consideration" and after weighing up all the evidence, including the "unsatisfactory and unreliable" evidence from Nash, she found police had proven the case beyond reasonable doubt.
In doing so, Nash "acted dishonestly and she had no belief that her actions in taking the bag were lawful".
Judge Mathers found Nash guilty but will not enter a conviction until sentencing in May.
