In this trade, the Net Annual Cap Hit added by Tampa is $4.125M. However, with Gaborik ($4.875M) & Nilsson ($2.6M) going to LTIR, Tampa actually gained $3.35M in effective cap space with the trade.
After this trade, Tampa can now possibly exceed the cap and have an LTIR pool to a maximum of $16.975M (Kucherov $9.5M, Gaborik $4.875M, Nilsson $2.6M). Their LTIR Pool will be determined by how much they are over the salary cap when they submit their roster. They're currently projected to be $16.52M over the cap (less than the maximum $16.975M), so their current roster would be cap compliant on opening day. This would mean their LTIR Pool, and how much they can exceed the cap, would be $16.52M this season.
Ottawa saved cash in the deal. They traded Gaborik ($3.075M Salary) and Nilsson ($2.4M Salary), and added Coburn ($1.6M Salary) and Paquette ($1.65M Salary) for $2.225M cash savings.