That can quickly become complex. Depends on what you mean by “side work.” Very generally, up to 25% of self-employed income (up to annually indexed limits) as a 1099 contractor can be contributed to a retirement account.
Age can factor in that there are some available catch-ups for those over 50.
What complicates it are health-care costs, whether she has an HSA, and other earned-income benefits and taxes paid. She may have to pay some self-employed social security and medicare taxes depending on her earned income, for example.
You have plenty of time to sort it out as contributions for 2019 will not be due until April 15 2020 (or perhaps later if on a fiscal tax year).
Complex may be an understatement: always seek competent local counsel before making any decisions.