damir4ig

Зачем вы делаете функцию внутри функции?

Сделайте так

@bot.message_handler(content_types=['text'])
def catalogchk(message):
    if message.text == "Каталог":
        catalogKBoard = types.ReplyKeyboardMarkup(row_width=2, resize_keyboard=True)
        Steam = types.KeyboardButton(text="Steam")
        Origin = types.KeyboardButton(text="Origin")
        UPlay = types.KeyboardButton(text="UPlay")
        EpicGames = types.KeyboardButton(text="Epic Games")
        VPN = types.KeyboardButton(text="VPN")
        catalogKBoard.add(Steam, Origin, UPlay, EpicGames, VPN)
        bot.send_message(message.chat.id, "Выберите Раздел", reply_markup=catalogKBoard)

Если вы хотите сделать отдельные функции для генерации клавиатур - сделайте так:

def start_keyboard():
    keyboard = types.ReplyKeyboardMarkup(row_width=1, resize_keyboard=True)
    Catalog = types.KeyboardButton(text="Каталог")
    Info = types.KeyboardButton(text="Инофрмация")
    keyboard.add(Catalog, Info)
    return keyboard

def catalog_keyboard():
    keyboard = types.ReplyKeyboardMarkup(row_width=1, resize_keyboard=True)
    Steam = types.KeyboardButton(text="Steam")
    Origin = types.KeyboardButton(text="Origin")
    UPlay = types.KeyboardButton(text="UPlay")
    EpicGames = types.KeyboardButton(text="Epic Games")
    VPN = types.KeyboardButton(text="VPN")
    keyboard.add(Steam, Origin, UPlay, EpicGames, VPN)
    return keyboard

Использование:

bot.send_message(message.chat.id, "Сообщение", reply_markup=catalog_keyboard())