It's good to get into seat with middle of stadium crowded (8)
I believe the answer is:
thronged
'crowded' is the definition.
(thronging is a kind of crowding)
'it's good to get into seat with middle of stadium' is the wordplay.
'it's good' becomes 'g' (abbreviation).
'to get into' indicates putting letters inside.
'seat' becomes 'throne' (throne is a kind of seat**).
'with' says to put letters next to each other.
'middle of' means to look at the middle letters.
The centre of 'stadium' is 'd'.
'g' going into 'throne' is 'thronge'.
'thronge'+'d'='THRONGED'
(Other definitions for thronged that I've seen before include "Gathered in numbers" , "Crowded like very busy street" , "Formed crowds" , "Swarmed" , "Gathered together in crowd" .)