They're close in meaning, but 'chitchat' is slightly more negative. Small talk is often necessary. For example, if you meet a business associate, you might begin the conversation with a few questions about whether it's his first time in the city, how his trip went, what the weather's like etc. It's normal to make small talk in this way for a short while, helping you to feel comfortable in each others' company, before starting to talk business. You wouldn't use 'chitchat' in the above context. Chitchat is trivial, and may carry with it an implication of being a waste of time, or that you are gossip-mongering. Interestingly, both 'gossip' and 'chitchat' collocate most commonly with the adjective 'idle'.

In Canada both of the words are interchangeable on a daily conversational level and even professional level (although 'chitchat' can be considered a little too relaxed so professionals tend to lean towards using words such as 'small talk', 'chat', or even 'mingle').

"chitchat" is mean any conversation about nothing or maybe it's gossips. For example: it's all nothing but empty chitchat/chatter. Everyone is able to chit chat with friends. Sure, you are going to talk about sports, the weather and other menial bits of information, but you are also going to move more into chit chat, which includes gossip. "small talk" is a light conversation that centers around unimportant topics, or at least uncontroversial topics. When making small talk with a potential client or customer, you do not want to bring up politics, religion or other ideas that can be viewed as controversial.

Basically no difference, both words would translate as Spanish "charlar": - Enough chit-chat, it's time to get to work. - Enough small talk, it's time to get to work. In a _very slight_ shading of meaning, "chit-chat / chitchat" is less purposeful than "small talk": - Their constant chit-chat (= talk without meaning) was annoying because it's so pointless. - Now that the small talk (= the weather, family health, sports, etc.) is out of the way, let's talk business.