Thanks for the clarification.
Staying away from kanji is a simple matter, because in Japanese anything that can be written in kanji can also be written in hiragana. Hiragana is a phonetic writing system which is capable of representing any sound that can be spoken in Japanese.
Three points to keep in mind:
- Japanese usually does not use spaces. There are a few specific cases where you will see spaces, including text aimed at beginning-level foreign students studying the language, and text written for young children. Other than those cases, though, it is more natural (and less "childish") to see Japanese text written without spaces. Even if you get an all-hiragana tattoo, I would recommend not using spaces, unless the text is so long that it becomes unwieldy to try to read.
- To optimally translate a message into a second language, it is important to first make sure that the precise meaning of the message is clearly conveyed. While I can guess what you mean by "chaos before wisdom", it is somewhat unclear, and could lead to an inaccurate translation if misunderstood by a person translating it. For that reason, I recommend that in addition to providing your desired message ("chaos before wisdom"), along with that you also provide a more detailed description of precisely what you consider the meaning of that text to be.
- Two different languages do not always express the same thought in the same way. When translating, there are two fundamentally different ways to translate: (1) a literal (essentially, word-for-word) translation, in which words of equivalent meaning are used in the target language, and (2) a meaning-based translation, in which the same message is expressed naturally in the target language, but perhaps using different words. Because English and Japanese often express ideas in different ways from each other, a literal translation might sound quite unnatural to a native speaker of Japanese. If it is important that your message sound natural in Japanese, then it is better to use a translation of type (2) above, even if it does not contain the exact same words as the English version.
There are numerous ways to translate your message into Japanese. One example is the following:
ちえはカオスからうまれる。
Back-translated literally into English, this message reads "knowledge is born out of chaos". This message as written here mostly uses hiragana, but also uses three katakana characters, to represent the word "chaos". This word is most commonly written using katakana, so keeping it in katakana is more natural than converting it into hiragana. And doing so also helps make the sentence easier to read. The period at the end is optional. Having it or not is a stylistic choice you can make.