You can install a chandelier yourself in certain situations, but it is not always the best idea.
If you are replacing an existing chandelier and the ceiling box is already secure and rated for the weight, the job may be manageable if you are comfortable with basic electrical work. That usually means turning off the breaker, removing the old fixture, connecting the new wires, and mounting the chandelier properly.
The complication is weight. Chandeliers are often heavier than standard ceiling lights. The electrical box needs to be firmly attached to a joist or support brace. If it is not designed to hold that load, it must be reinforced before anything is hung from it.
Ceiling height is another factor. Working on a tall ceiling can be tricky and sometimes requires special ladders or extra help. Older homes may also have wiring that should be inspected before connecting a new fixture.
If you are adding a chandelier where no light existed before, you will need new wiring and possibly structural support. That is usually a job for a licensed electrician.
A chandelier should feel solid and steady. If you are confident and the setup is straightforward, you may be able to handle it. If there is any doubt about wiring or support, bringing in a professional is the safer move.