The expectant couple opted for a neutral-toned decor with a white wooden cot from Quirky Bubba, off-white walls and a trendy rattan arch cupboard from Junimoon furniture store.
Alex also incorporated a custom olive green nursing chair from Cullen Design, with three framed native animal paintings by artist Maku Fenaroli.
"Creating this space for baby J was extremely emotional and special for me," Alex captioned her Instagram post.
"What started as a neglected plain old 1960s room with four layers of carpet and vinyl is now a beautiful, traditional country-styled nursery thanks to my most handsome and handy fella."
The 29-year-old also took a trip down memory lane and revealed to her 100,000 followers that she had a very different nesting experience with her first child Elijah, 10.
"When I was pregnant with Elijah, I was young with very little money and living with my mum," she wrote.
"Elijah shared a very small space with me during his early years and I never had the chance to be able to create his own special room. I remember at the time feeling guilty that I couldn't do so.
"Looking back though, I do cherish the memories of him falling asleep and waking up next to me every day as a toddler, even though sometimes he would just sleep all over me and I'd constantly cop limbs to the face during the night."
Earlier this month, Alex celebrated her baby shower with Carson, Elijah and close friends and family.
“How lucky Elijah and I are to call Carson’s loved ones our own and how loved baby J already is. A day with family and friends celebrating such a magical time," she captioned a series of photos from the event.
"To our family and friends, thank you for welcoming me with the most open arms right from the very beginning.”
The former Bachelor and Bachelor in Paradise star shared photos of a bespoke cake adorned with native flowers, dozens of cupcakes and personalised cookies for guests.
The soon-to-be mother-of-two first hit our screens on season four of The Bachelor, winning Richie Strahan's heart. The couple dated for a year before eventually calling it quits.