。
She loves watching tennis matches on TV.
Literal
She [topic-は] TV [on-で] tennis [genitive-の] match [object-を] watch [thing-の] [subject-が] really-likes.
Two structural pieces. The noun-clause 見るのが is the standard nominalization frame for 'doing X': nominalizer の + が, where 好き ('like') and 大好き ('love') take their object with が, not を, since they're stative predicates of preference. テレビで means 'on TV' — で here marks the medium/means by which the watching happens. Pair this with テレビに出る ('appear on TV') and you see how the same medium takes different particles depending on what's happening: で for using as a means, に for becoming present in.