"never the less"="eventhough"?

??

Basically, yes.

Not used in exactly the same way though.

"Even though" is used as a conjunction between two contrasting clauses, while "nevertheless" is used at the beginning of a new sentence, to contrast its meaning with the preceding one. An example:

"Peter won the race, even though John has more training."
"John has more training than Peter. Nevertheless, Peter won the race."