I presume the reply has been sent/ visit has happened now, but I will answer anyway as it has been bumped by something.
This is a very clunky sentence. Lets start with the first half
I would be very happy if I could have such an opportunity to see you
the "If I could have" is fine at the very start of a clause for example
"Ladies and Gentlemen, if I could have a moment of your time".
It is not okay in the middle, it stops the flow, I am going to get all poetic a sentence is a river it should flow smoothly downstream. That phrase is a huge bolder stopping the river flowing smoothly, it makes the talker/ reader have to manoeuvre around it.
How would i word this? I would replace that whole boulder with the simple phrase "for the"
I would be very happy for the opportunity to see you in person
So onto the second part
so please let me know whenever (if?) you will have a chance to visit
once again "you will have a chance" doesn't flow but this is ok in the current construct as the brackets are read as commas making it the start of a new clause.
Take the If out and try to read this clause out loud using a natural pace, "whenever you will have a chance" is quite a tongue twister.
So what would I say
so please let me know whenever you will be visiting the area
the word whenever implies it maybe not happening.
1 At whatever time; on whatever occasion
(emphasizing a lack of restriction)
‘you can ask for help whenever you need it’
Hopefully somebody will be along to correct/ explain the grammar of it all.