Yes you can eat chocolate when it's a month out of date.
Chocolate does not really go bad as in the chocolate will not go bad and make you sick if you do eat it well past the expiration date.
You can eat chocolate that has been expired for 10 to 20 years and not get sick from it.
Although when chocolate expires and goes bad it just loses it's taste and texture and may not be as good to eat or enjoyable.
But it's safe to eat or consume chocolate even when it's been out of date for months and even years.
I've eaten chocolate that I've had and forgotten about for 5 years and it was still very safe to eat.
The chocolate didn't taste as good but it was okay as in it didn't make me sick.