A huge amount in park for The Boss, the lead from Oasis and Queen in Los Angeles (8)
I believe the answer is:
plethora
'a huge amount' is the definition.
'plethora' can be an answer for 'amount' (I have seen 'Excessive amount' mean 'plethora' so perhaps 'amount' could also mean 'plethora'). I'm unsure of the 'a huge' bit.
'park for the boss the lead from oasis and queen in los angeles' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'the' is 'eth' which is present in the answer.
'queen' could be 'r' (r is abbreviation regina. e.g. in ER ) and 'r' is present in the answer.
This explanation may well be incorrect...
'in' acts as a link.
Can you help me to learn more?
(Other definitions for plethora that I've seen before include "flood" , "Oversupply" , "Superabundance" , "Excess, glut" , "Excessive quantity" .)