Help with a swarm

[Cascadebee]

I got called for a swarm that I'm not sure how to deal with.  They were flying like crazy in a corner of the house adjacent to the chimney.  There are vent holes on the chimney and some bees were coming and going from there but many were not, they were flying in circles.  I put out a nuc box and with a couple drops of lemongrass and some bees found it right away and started fanning at the entrance.  I stayed for an hour and by the end there were more bees around the entrance of the nuc (coming, going, fanning), but more still flying and some still in the chimney.  I left the box there. 

Thoughts?

I'm considering placing a cone over the chimney vents, I think the queen is probably in there. I don't have a cone I would have to make it. 

Thanks.

[MacfromNS]

Sounds like a plan, let us know how you make out.