I would roll your old 401k out to an IRA first. You have more flexibility in investment options and tax efficient strategies.
Then determine if you can make an IRA contribution (Roth vs Traditional depends on your income). If you made contributions to the old 401k in 2021, then you are considered a participant in that 401k for 2021 and it plays a factor in determining whether you can make a deductible IRA contribution like what slackster said. Depends on your income and how much you have contributed already in 2021.
So, for example, if you’re 45 years old and are going to make $100k gross this year and you contributed $15k already to your old 401k, then you should roll out your old 401k to an IRA and make a $6,000 IRA contribution.
This post was edited on 11/2 at 8:57 am