Video footage shows a brazen thief jumping out of a car and running up to the front porch to nab the Amazon parcel, before leaping back into the vehicle.
But as the getaway driver speeds off, she loses her footing and tumbles out, ending up in a heap on the pavement.
Watching the melee unfold outside, the family's nanny Kate Anderson sprinted outside to take matters into her own hands.
"I saw her bending and picking it up, and they get a lot of packages," Anderson told KIRO .
"And I knew. I was like, 'Oh my gosh, she's taking that,' so I just took off after her, to be honest."
As the thief stands up, she tries to tackle her to wrestle the parcel from her hands without a second thought for her own safety.
Anderson yells: "Hey what the f**k are you doing? Hey you piece of s**t what are you trying to steal?"
At one point, the woman tried to run away before Anderson shouts: "I am not letting you go."
Police arrived and arrested the woman, later identified as 29-year-old Rhieanna Schindler, who was already wanted for drug possession and theft.
She has been arrested more than 20 times since 2010.
The incident happened in Everett, Washington.
Speaking of her courageous actions, Anderson said: "I didn't ever feel like she was a threat to me.
"So I think I would've handled it the same way, yes, because it's just not okay to go around doing that. It's so not okay with me," she said.
Anderson's employer and friend, Tanya Smith, who is mum to one-year-old Desmond, said she's proud of what she did.
"She's just like a straight baller, she's amazing and doesn't take any crap from anybody,"she said.
"It's pretty amazing what she did, I'm very proud of her, and I'm not surprised."
She has now created a GoFundMe page to raise $200 to reward her 'Rambo Nanny;.
"Kate Anderson not only takes amazing care of my son, but bravely chased down a thief who was stealing from our front porch and restrained her until the police came," Smith wrote on the page for the fundraiser that's raised more than $270.
"She's truly a modern-day hero and deserves a reward for her admirable actions.
The package that was stolen was filled with items for the Desmond, who slept through the entire thing.
Snohomish County Sherrif's office say they do not condone what she did, but wanted to let her know they are hiring.