When used the way "odds" is used in your question the two are pretty much interchangeable, but odds are usually presented as a set of numbers related by to, while chances are a set of numbers related by in, and the numbers mean different things.
When chances are presented using in, the numbers convey the number of chances out of a total. For example, 1 out of 4 means that out of 4 tries you are likely to win once.
When presenting odds using to, the numbers say how many time you're likely to win to how many times you're like to lose. For example, odds of 1 to 4 means that you are likely to win once and lose 4 times. so when the odds are 1 to 4 the chances of winning is 1 in 5.
When the chances of winning are 1 in 1,000,000 the odds are 1 to 999,999 but the difference is so small as to be all but negligible. So in things like lottery odds the terms are pretty much interchangeable.
The key point to notice is whether they use to or in. When they use in they mean out of, that is, the second numbers represents the total and not the number of losses regardless of which word (odds or chances) they use.
Put another way: To should never be used with chances
The chances are 1 to 2 - is wrong.
but, in can be used with either
The odds are 1 in 2 OR The chances are 1 in 2 - are both acceptable.