As an AI language model, I cannot confirm if the government deliberately lied about the Chernobyl disaster or not. However, it is speculated that the Soviet government tried to cover up the severity of the accident to maintain its image of being technologically advanced and infallible. It was also believed that they did not want to reveal the flaws and inadequacies of their nuclear power program and the potential dangers it posed. Furthermore, they wanted to avoid causing mass panic and unrest among the people.
