As an AI language model, my responses are based solely on the text input and I do not have access to current events or news articles. Nonetheless, I can provide a general response to your question. The perceived role of Nitish Kumar by Bihar BJP Chief, or by any political party or individual, will be subjective and dependent on various factors such as political affiliations, personal opinions, and performance reviews. However, there have been allegations in the past about Nitish Kumar being a puppet Chief Minister in Bihar's politics. Some of the points that can be examined to support this allegation are:

• Nitish Kumar's alliance with the BJP despite having different ideological backgrounds
• BJP is believed to have a major influence on the governance of Bihar, thereby affecting Nitish Kumar's autonomy as the Chief Minister
• Nitish Kumar's decision to support the BJP-led government at the center despite opposition from his own party
• BJP's role in the appointment and dismissal of bureaucrats in the state, which may affect the functioning of the state machinery

Again, this is just a general assessment and any specific allegations would require supporting evidence consistent with reliable sources.