If you're talking about a single talent show:
* It: "The talent show was a huge success." -> "It was a huge success."
* That: "I went to a talent show last night." -> "I went to that last night."
If you're talking about talent shows in general:
* They: "Talent shows are popular forms of entertainment." -> "They are popular forms of entertainment."
* These: "The judges on these are often very critical." -> "The judges on these are often very critical."
* Such events: "I'm not a fan of such events." -> "I'm not a fan of such events."
If you're being specific about a type of talent show:
* Those: "Singing talent shows are very popular." -> "Those are very popular."
Ultimately, the best pronoun depends on what you are trying to say and the context of your sentence.