This story is part of CNBC Make It's Six-Figure Side Hustle series, where people with lucrative side hustles break down the routines and habits they've used to make money on top of their full-time jobs. Got a story to tell? Let us know! Email us at AskMakeIt@cnbc.com.

Megan Walsh grew up listening to the sound of her mom's Singer sewing machine, thudding against Halloween costume fabric.

It's one of Walsh's favorite childhood memories, giving her an appreciation for the way handmade things smell, feel and resonate with people, she says. And it inspired the part-time endoscopy nurse's lucrative side hustle, which she launched from her living room in Manahawkin, New Jersey.

Walsh, a lifelong crafter, opened her Etsy shop MegansMenagerie in 2009. Last year, the shop — which currently specializes in plant-themed wall decor — brought in more than $121,400 in revenue last year, according to documents reviewed by CNBC Make It. Through September, it's on track to bring in over six figures for the third consecutive year.

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The shop isn't always popular. Sometimes, Walsh finds a type of craft that sells well, and revenue jumps. In 2012, for example, she found success selling chevron scarves — sewn with the same Singer machine — and made enough to buy a then-new Dodge Journey SUV, she says.

Other times, the shop is simply a place for her to offload her art and get a little help paying everyday bills. The side hustle has helped cover monthly student loan payments, a used car for one of her daughters, vacations and a vow renewal ceremony, says Walsh.

Since Walsh began selling wall decor in 2021, she's pocketed roughly $60,000 per year from her side hustle, she estimates — close to what she makes annually as a part-time nurse. She works about 12 to 24 hours per week on her shop and 24 to 32 hours at a hospital, she says. If her Etsy income falters, she can pick up more nursing hours, she adds.

Here, Walsh discusses juggling her side hustle with her nursing job, avoiding burnout and why she's happy with a side hustle isn't guaranteed to make money forever.

CNBC Make It: Is your side hustle success replicable?

Walsh: Definitely. I just think it takes a lot of drive [to run a side hustle]. It's not easy, and you need to find the right balance between hustle and happiness.

I've found things that I've enjoyed creating, made a little money, then the trends have gone away. Then, I fall into something else. Everyone wants to make money, but you can't be so overcome with busyness that you miss your entire life.

Is balancing a side hustle with your nursing career difficult? Do you have any strategies for avoiding burnout?

Yeah. I'm a multi-tasker, and I love to do all these things all the time. If I feel like I'm doing too much, I know I have to give something up. I was a forensic nurse [helping sexual assault survivors] for years, but I stopped [after the Etsy shop took off in 2021] because I felt like there weren't enough hours in the day.  

If you're burning yourself out, you're going to miss your whole life. Every single day, I wake up and set an intention — usually in my head, sometimes in my journal — for the amount of work I'm going to do, and I don't push past that.

My littlest is in fourth grade, and he just had his first school play, so it was a lot of running around and late pickups on top of the normal homework, shower, dinner routine. On days like that, I know that I'm not going to get a lot done, so I plan a day where I can either work ahead or catch up when my kids aren't around.

I set boundaries and cut back when I need to. Sundays are a family-only day.

Your side hustle's sales history is full of peaks and valleys. If plant-themed wall decor stopped being popular tomorrow, would you start looking for the next trendy craft?

No. This shop has kept me very, very busy for years, and I welcome the slowdown. My husband tells me I'm a workaholic, but actually, I just like to ride things out while they're hot. The planning is tough sometimes, and I don't know what my next thing is going to be.

I've always just made things I like, and starting making them because it was something I enjoyed. I'll never stop making things. It's what keeps me grounded.

This interview has been edited and condensed for clarity.

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