That really depends on what you mean by privacy. They probably won‘t sell your data or even look at the stuff you‘re doing with your server, if you‘re not disrupting their service. But they definitely will cooperate with law enforcement if your server is used for illegal stuff and someone reports it.
In the end, you’ll always have to trust your server host to some degree. Some other hosts, like Hetzner, allow you to install your own operating systems on their dedicated servers, so you can set up full disk encryption. But even though this is definitely better than unencrypted disks, it‘s still not a reliable way of preventing access while your server is running.
So if you’re just wondering if you can host a Nextcloud instance at hostinger without your files being sold by them: Almost certainly, yes. If you, on the other hand, plan to host manuals for building bombs or, even worse, offer downloads of old Nintendo games, they‘re probably not going to respect your privacy for long.
I‘d probably go with a VPS. It probably won‘t cost more than 10$/month, maybe even less, depending on how much heavy usage your Nextcloud instance requires. And you won‘t have to worry about keeping your hardware and network running, which pretty much always takes up more time than expected.
Some web hosters (I‘ve had very good experiences with Hetzner) charge an hourly rate and allow you to preconfigure VPSes with software like Nextcloud. So unless you have specific needs, you could just spin up an instance, check if it suits your needs and, if not, only pay a few cents.