According to the Daily Mail, Nickayla is helping Ryan care for his son and her nephew, Josey, who was with Naya on the day she drowned in Lake Piru.
The pair, who have leaned on each other for support since Naya's passing, have reportedly been "inseparable" and moved into a three-bedroom house together last week.
A source told the publication: "They seem really comfortable together and are obviously helping each other through a very difficult period in both their lives."
"They were fooling around and chatting the whole time. They're obviously helping lift each other's spirits."
Ryan took to Instagram following Naya's death to share a touching tribute to his ex.
He wrote: "This is so unfair...there's not enough words to express the hole left in everyone's hearts. I can't believe this is life now. I don't know if I'll ever believe it.
"You were just here... We were just in the back swimming with Josey the day before. Life just isn't fair. I don't know what to say...I'm thankful for our times and our journey that brought us together and gave us the sweetest and kindest smart little boy we could ever hope for."
He continued: "I remember sometimes you used to get annoyed at me: 'Ryan can you stop snap chatting!' Haha. I'm glad I didn't listen to you because I have hundreds and probably thousands of snaps and videos that Josey will have forever and know his momma loved him more than life, and how much fun we had together as he was growing up.
"Life is all about good times and bad times but with Josey it makes the bad a little less so because a part of you will always be with us. He'll never forget where he came from. We miss you. We will always love you. Love you Meep."
Ryan shared a message of thanks to those that had reached out to him calling the love and support he received "overwhelming".
He finished by saying: "Hold your loved ones close, and cherish the times you have with those you care about."
Nickayla also shared a tribute to her sister, writing: "Sister, there are no words to describe my love for you. Side by side or miles apart, our connection is infinite.
"Our bond is unbreakable. We were complete opposites, yet simultaneously the same. The yin to my yang. I never knew that by losing you, I would find so much of you in myself.
"I’ve never known a life without you in it & still can’t imagine it. My world is turned upside down. But through it all, everything we were, we are still. I’ll always look at you with the same eyes as I did when I was young.
"My shmaya, I’ll love you for eternity & miss you every second of my life."